Try these
Sumdog Free maths games to improve numeracy skills for 9 to 13 year olds.. Create studentx login so that they can click on a game, login, and practise their maths.
Teachers can create Sumdog logins for a whole class at once - no e-mail addresses needed. Teacher signup is free: http://bit.ly/92uhcz
You can use the numeracy topics in your lessons in several different ways - for example, as an engaging introduction to mental maths, or to reinforce one specific topic..